Process of manufacturing cellulose-stock from cotton-seed hulls and products thereof.



UNITED STATES PATENT OFFICE.

THOMAS NE\VSOME, OF ROSLINDALE, MASSACHUSETTS, ASSIGNOR, BY MESNE ASSIGNMENTS, TO AMERICAN BY-PRODUCTS COMPANY, OF

NEW JERSEY.

PROCESS OF MANUFACTURING CELLULOSE-STOCK FROM COTTON-SEED HULLS AND PRODUCTS THEREOF.

SPECIFICATION forming part Of Letters Patent No. 683,785, dated October 1, 1901. Application filed March 29, 1901- Serial No. 53,516. -(N Specimens-l To all whom it may concern:

Be it known that I, THOMAS NEWsoME, of Roslindale, county of Suffolk, State of Massachusetts, have invented a new and useful Process for the Manufacture of Cellulosic Stock from Cotton-Seed Hulls and the Products Thereof, of which the followingis a specification.

My invention relates to processes for the production of fibrous cellulose suitable for the manufacture of high-grade papers and for other purposes where absolute purity of stock is essential. Its object is to secure such a product from cotton-seed hulls; and it consists in the process and resultant product hereinafter described and claimed.

The short fiber or fuzz remaining upon cotton-seed after the ginning process, commercially known as linters, while too short in staple for use in the manufacture of textiles is well adapted for paper-making and for uses where length of staple is unimportant, provided it can be freed from the seed-shells and all dirt and other matter except pure fiber eliminated.

The cotton fiber or hair in its ripe or mature state is in form a collapsed tube, more or less twisted and otherwise distorted. It carries in its interior and also as an outside covering or membrane certain waxes of refractory character, being insoluble in Water and only partially soluble by the use of caustics. These waxes render the fiber to a considerable degree non absorbent and are highly deleterious, as are other Waxy or resinous substances in paper-making and in other arts where pure cellulose is demanded, although they are not specially objectionable in textile manufacture. In reducing such material to fiber it is essential that whatever agencies are relied upon the fiber shall not become oxidized or otherwise impaired, as is liable to result from treatment with caustic liquors. I have discovered that a volatile hydrocarbon, such as naphtha, will completely dissolve the waxes contained in and deposited upon the fiber as well as the cementitious material of the seed-shells and the oils and gums present in the hulls without attacking or injuring the fiber. The seed-shells aftersuch treatment are so broken down that for their complete dissolving and elimination a caustic liquor so weak as to be innocuous to the fiber suffices.

My process in detail is as follows: I first treat the bran or hulls with the vapor of a liquid hydrocarbon, such as naphtha, in a suitable digester which is in cycle with a vapor-generator. The vapor as generated is carried, preferably, into the top or upper part of the digester and forced downward through the mass of material, being itself condensed and dissolving and carrying away with it the oils, fats, waxes, and gums in the material. This step of the process is coutinueduntil these have been entirely removed from the material, being carried from the digester into the generator, where they accumulate, the hydrocarbon itself being continuously revaporized and passed through the mass until this step is complete. Hot air is then preferably forced through the material in order to free it from any remaining traces of hydrocarbon. The material is then removed from the digester and placed in another digester and there treated under pressure with a Weak caustic solution until the hulls or shell-like portions are disintegrated and separated from the fiber, after which the mass is removed and the fiber thoroughly washed to free it of the alkali and other matter. While the strength of such caustic solution, the degree of pressure employed, and the period of treatment may all be interchangeably varied within certain limits, I prefer to use a solution of about two per cent. of caustic soda under a steampressure of about sixty pounds, continued for a period of about four hours. After the fiber has been washed it may be and usually is bleached by ordinary methods to the desired degree of whiteness.

\Vhen it is desired to save the coloringmatter existing in the cotton-seed hulls for the purpose of manufacturing a dye, the hulls may be treated for that purpose before being treated with the described caustic solution for securing the fiber, or the color may be obtained from the liquor of the caustic solution after treatment of the material by neutralizing the alkali as far as may be necessary with suitable acids. 1 r a In some cases it may be desirable that all handling of the material during the process be avoided and that the apparatus be in as compact and small compass as possible. In such case a suitable digester may be employed, which may be alternately coupled or placed in cycle with the other parts of the apparatus by means of which the several steps of the process are performed.

By my improved process above described all of the valuable lint or cotton fiber remaining attached to the bulls of the cottonseed after it has passed through the cotton gin or linter may be saved practically free from all foreign matter and with its strength unimpaired. The freeing of fiber or cellulosic stock from waxes and gums is due tov the treatment with hydrocarbon. Hence there is no saponifying action and the fiber or cellulosic stock is secured practically without diminution of quantity or deterioration in quality. The fibrous product remaining after such treatment is clearly distinguishable from cotton as produced by nature or as it enters the arts after the ordinary treatments of bleaching, washing, doc. Under the microscope the individual fibers of the latter appear partially, if not wholly, opaque and more or less bent and twisted. It is not readily absorbent of water, because of the presence of the waxes and gums in and upon the fibers. On the other hand, the product resulting from my process is free of the waxes and gums, and as a result is perfectly absorbent of water. The individual fibers under the microscope appear materially enlarged in diameter, and nearly, if not entirely, deprived of their natural twist, and are translucent throughout their entire diameter. This new product, because of its being a pure cellulose, constitutes an ideal stock for fine paper making and for use in the arts generally where absolute purity is required.

I claim- 1. As a new product, cotton fiber deprived of its natural waxes.

2. The cellulosic stock, comprising the linters of cotton-seed, deprived of the natural Waxes and freed from the seed-shells and other foreign matter.

3. The process of producing a cellulosic stock from the hulls of cotton-seed withoutsaponification, consisting in first eliminating the oils, fats, waxes and gums from the material by means of a suitable solvent, then treating the material with a weak caustic solution to disintegrate the seed-shells, and then washing the fiber.

4. The process of securing thelinters from cotton-seed hulls free from the seed-shells and deprived of the oils, fats, waxes and gums, which consists in first treating the material with hydrocarbon vapor until such oils, fats, waxes and gums are dissolved and removed therefrom; then freeing the material from the hydrocarbon; then treating it with a weak caustic solution under pressure until the seed-shells are disintegrated, and then washing the linters to remove all foreign material.

5. The process of producing pure cellulose from cotton-seed linters, consisting in first treating the bulls or other cotton-seed material with a hydrocarbon vapor under pressure, to dissolve and remove the oils, fats, Waxes and gums, then extracting the coloring-matter and dissolving the seed-shells with a caustic solution under pressure, and then washing and bleaching the fiber.

6. The process of securing the linters or fiber in cotton-seed hulls or other material, consisting in first eliminating the oils, fats, Waxes and gums from the material by means of a suitable solvent without saponification; then eliminating the solvent from the material; then extracting the coloring-matter from the material and dissolving the shells by means of a caustic solution under pressure; and then washing and bleaching the remaining fiber.

Signed at Philadelphia this 12th day of March, 1901.

THOMAS NEWSOME.

Witnesses:

W. S. ANDERSON, T. W. LYND. 

